The Present Disclosure relates generally to high speed data transmission systems suitable for use in transmitting high speed signals at low losses from chips or processors of a chip package to backplanes and devices, and more particularly to connectors suitable for use in integrated connector interface-chip package routing assemblies.
Electronic devices such as routers, servers, switches and the like need to transmit data at high data transmission speeds in order to serve the rising need for bandwidth and delivery of streaming audio and video in many end user devices. Chips are the heart of these routers, switches and other devices. These chips typically include a processor such as an ASIC (application specific integrated circuit) or an FPGA (field programmable gate array) and the like, these chips have dies that are typically connected to a substrate (creating a package) by way of conductive solder bumps or other convenient connection. The package may include micro-vias or plated through holes that extend through the substrate to solder balls. These solder balls comprise a ball grid array by which the package is attached to the motherboard. The motherboard includes numerous traces formed in it that define transmission lines which include differential signal pairs for the transmission of high speed data signal, ground paths associated with the differential signal pairs, and a variety of low speed transmission lines for power, clock and logic signals as well as other components. These traces include traces that are routed from the ASIC to the I/O connectors of the device into which external connectors are connected to provide a connection between one or more external plug connectors and the chip member. Other traces are routed from the ASIC to backplane connectors that permit the device to be connected to an overall system such as a network server or the like.
These conductive traces thus form transmission lines as part of the mother board and extend between the chip member and connectors to provide that provides a connection between one or more external plug connectors and the chip member. Circuit boards are usually formed from a material known as FR4, which is inexpensive. Although inexpensive, FR4 is known to promote losses in high speed signal transmission lines that transfer data at rates of about 6 Gbps and greater. These losses increase as the speed increases and therefore make FR4 material undesirable for the high speed data transfer applications of about 10 Gbps and greater. This drop off begins at about 6 Gbps (or 3 GHz using NRZ encoding) and increases as the data rate increases. In order to use such traces in FR4, a designer may have to utilize amplifiers and equalizers, which increase the final cost of the device.
Custom materials for circuit boards, such a MEGATRON, are available that reduce such losses, but the prices of these materials substantially increase the cost of the circuit board and, consequently, the electronic devices in which they are used. Additionally, when traces are used to form signal transmission lines, the overall length of the transmission lines can exceed threshold lengths at which problems to appear in operation. These lengths may approach 10 inches and longer in length and may include bends and turns that can create reflection and noise problems as well as additional losses. Losses can sometimes be corrected by the use of amplifiers, repeaters and equalizers but these elements increase the cost of manufacturing the circuit board. Do so, however, complicates the design inasmuch as additional board space is needed to accommodate these amplifiers and repeaters. In addition, the routing of the traces of such a transmission line may require multiple turns. These turns and the transitions that occur at terminations affect the integrity of the signals transmitted thereby. These custom circuit board materials thus become more lossy at frequencies above 10 Ghz than cable transmission lines. It then becomes difficult to route transmission line traces in a manner to achieve a consistent impedance and a low signal loss therethrough.
It therefore becomes difficult to adequately design signal transmission lines in circuit boards and backplanes to meet the crosstalk and loss requirements needed for high speed applications. Accordingly, certain individuals would appreciate a cable connector suitable for use in integrated, high speed, connector interface-chip package routing assembly that provides transmission lines for transmitting high speed data signals (above 20 Gbps) without using traces on the circuit board.